Indicator Light Symbol

I am new to the forum and hope someone out there in BMW land can clue me in on a indicator light symbol. I just purchased a 2000 323 i. The car did not come with an owners' manual although the seller has ordered a replacement. On my drive home from work, an indicator light came on and I don't know what it is for. The symbol is located in the lower right corner of the indicator light 'panel' on the dash instrument panel. The shape is like a box with 'teeth' is about the best I can do to describe it.

Any help on identifying this item will be most helpful and I hope it is not a serious warning light.